metamask-extension/app/scripts/migrations/044.js

import { cloneDeep } from 'lodash';

const version = 44;

/**
 * Remove unused 'mkrMigrationReminderTimestamp' state from the `AppStateController`
 */
export default {
  version,
  async migrate(originalVersionedData) {
    const versionedData = cloneDeep(originalVersionedData);
    versionedData.meta.version = version;
    const state = versionedData.data;
    versionedData.data = transformState(state);
    return versionedData;
  },
};

function transformState(state) {
  if (
    typeof state?.AppStateController?.mkrMigrationReminderTimestamp !==
    'undefined'
  ) {
    delete state.AppStateController.mkrMigrationReminderTimestamp;
  }
  return state;
}